A growing number of baseball and softball players alter bat barrels in an effort to increase the performance of ball bats. Ball players, for example, have been known to remove a bat's cap and to shave or machine away material from the inner surface of the bat barrel to reduce the weight of the bat, which results in increased bat speed—and better bat performance—when the player swings the bat and strikes a ball. Once the cap is replaced on the bat, the tampering with the interior of the bat is generally undetectable.
Some ball players have also been known to induce delamination between the composite layers in a composite bat barrel. This delamination lowers the barrel's compression and increases the barrel's flex, which can enhance the bat's performance. The most common method for causing barrel delamination is “rolling,” wherein the bat barrel is placed between two cylinders oriented transversely to the barrel's long axis. The cylinders are then compressed into the bat while being rolled along the barrel to cause extreme deflections in the barrel structure. This process causes micro-cracking in the bat laminate, which eventually leads to delamination between the composite barrel layers. While this process generally reduces the bat's useful life, too many players opt for temporary enhanced performance over durability. As with shaving, alterations in the bat barrel resulting from rolling are typically undetectable by an observer.
In response to these bat-tampering methods, regulatory associations have begun to impose limitations on bat designs. The National Collegiate Athletic Association (NCAA), for example, has implemented a test that requires all bats to comply with performance limits even after they are rolled an unlimited number of times. Essentially, the bat must either remain below the maximum allowable performance limit or must break during the rolling. Accordingly, it is becoming increasingly challenging to design a high-performance ball bat that meets the requirements of regulatory associations. Nearly all other baseball and softball sports governing bodies, for example, the Amateur Softball Association (ASA), the United States Specialty Sports Association (USSSA), Little League, and so forth have adopted similar regulations.